1. Field of the Invention
This invention relates to liquid dispensers, and in particular to devices for dispensing quantities of liquids, such as cleaning liquids and liquids containing a dissolved cleaning product, from under the rim of a toilet bowl.
2. Description of the Related Art
Toilet bowls require care to prevent the buildup of unsightly deposits, to reduce odors and to prevent bacteria growth. Traditionally, toilet bowls have been cleaned, deodorized and disinfected by manual scrubbing with a liquid or powdered cleaning and sanitizing agent. This task has required manual labor to keep the toilet bowl clean.
In order to eliminate the manual scrubbing, various automatic continuous cleaning toilet bowl cleaning products have been proposed. One type of product comprises a solid block or solid particles of a cleansing and freshening substance that is suspended from the rim of a toilet bowl in a container that is placed in the path of the flushing water. U.S. Pat. No. 3,529,309 shows an example of this type of toilet bowl cleaning system. Typically, a portion of the solid block is dissolved in the flush water with each flush, and the flush water having dissolved product is dispensed into the toilet bowl for cleaning the bowl. These solid block toilet cleaning systems have certain disadvantages such as a short lifetime and a decline in the amount of cleaning and deodorizing agents released into the toilet bowl as the solid block deteriorates.
Other automatic, continuous cleaning, toilet bowl cleaning systems use a liquid cleaning agent that is dispensed into a toilet bowl. For example, European Patent Application Nos. EP-0538957 and EP-0785315, U.S. Pat. Nos. 6,178,564 B1 and 6,230,334 B1, and PCT International Publication Nos. WO 99/66139 and WO 99/66140 all disclose cleansing and/or freshening units capable of being suspended from the rim of a toilet bowl for the purpose of introducing liquid active substances from a bottle into the flushing water with each flush. Typically, the liquid active substances may include one of more of the following: surfactants (such as a mixture of an anionic surfactant and a nonionic surfactant), solvents, sequesterants, pH controllers, thickeners, preservatives, fragrances, and dyes.
While these under the toilet rim liquid dispensing toilet bowl cleaning systems provide an improved alternative to the solid block toilet cleaning systems described above, it may be difficult to incorporate certain toilet bowl cleaning actives, such as bleaches and various hypochlorites, into the liquid active substance. In this regard, bleaches and hypochlorites may affect properties of the components of the liquid active substance. For example, bleaches and hypochlorites will typically fade the color of a dye and destroy a fragrance upon extended contact. Also, certain incompatible cleaning actives may not be stable when mixed and through the resulting chemical interaction, the efficacy of the individual cleaning actives may be decreased. For instance, the efficacy of certain surfactants may be decreased by bleaches and hypochlorites. These limitations in liquid dispensing cleaning systems have prevented the optimization of toilet bowl cleaning active substances in one liquid formulation. In particular, the inability to incorporate bleaches and hypochlorites into a liquid active substance is especially detrimental as bleaches and hypochlorites are particularly effective in destroying bacteria and preventing biofilm formation.
Binary cleaning systems have been proposed for certain applications such as drain cleaning. See, for example, U.S. Pat. No. 3,968,048. In such systems, the components are separately stored and mixed at the time of use. However, manual mixing defeats the automatic nature of toilet bowl cleaning systems, and automatic mixing systems suitable for administering such two part cleaners are too large and bulky for mounting under a toilet bowl rim.
One disadvantage with both solid block toilet bowl cleaning systems and liquid dispensing toilet bowl cleaning systems is the timing in which liquid substances are delivered to the toilet bowl. Often, the dissolved solid product and the liquid substances are only delivered to the toilet bowl during a toilet flush. However, it has been discovered that one key to more effective toilet bowl cleaning is having some cleaning actives remain in the bowl after the flush. As a result, solid block toilet bowl cleaning systems and liquid dispensing toilet bowl cleaning systems that only deliver active cleaning substances to a toilet bowl during a flush may not achieve maximum cleaning effectiveness.
Therefore, there is a need for an improved device that can dispense quantities of cleaning and freshening liquids from under the rim of a toilet bowl both during and after a flush and that can deliver a greater variety of cleaning actives to a toilet bowl, including incompatible cleaning actives.